Canon 6D Mark II vs Pentax K-3 III

The Canon EOS 6D Mark II and the Pentax K-3 III are two enthusiast cameras that were revealed to the public, respectively, in June 2017 and March 2021. Both are DSLR (Digital Single Lens Reflex) cameras that are based on a full frame (6D Mark II) and an APS-C (K-3 III) sensor. The Canon has a resolution of 26 megapixels, whereas the Pentax provides 25.6 MP.

Below is an overview of the main specs of the two cameras as a starting point for the comparison.

Headline Specifications

Canon 6D Mark II		Pentax K-3 III
Digital single lens reflex		Digital single lens reflex
Canon EF mount lenses		Pentax K mount lenses
26 MP – Full Frame sensor		25.6 MP – APS-C sensor
1080/60p Video		4K/30p Video
ISO 100-40,000 (50 - 102,400)		ISO 100-160,000
Optical viewfinder		Optical viewfinder
3.0" LCD – 1040k dots		3.2" LCD – 1620k dots
Swivel touchscreen		Fixed touchscreen
6.5 shutter flaps per second		12 shutter flaps per second
Lens stabilization only		In-body stabilization
Weathersealed body		Weathersealed body
1200 shots per battery charge		800 shots per battery charge
144 x 111 x 75 mm, 765 g		135 x 104 x 74 mm, 820 g

Check 6D Mark II price at
amazon.com
Check K-3 III price at
amazon.com

Going beyond this snapshot of core features and characteristics, what are the differences between the Canon EOS 6D Mark II and the Pentax K-3 III? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.

Body comparison

The side-by-side display below illustrates the physical size and weight of the Canon 6D Mark II and the Pentax K-3 III. The two cameras are presented according to their relative size. Three consecutive views from the front, the top, and the rear side are shown. All size dimensions are rounded to the nearest millimeter.

The K-3 III can be obtained in two different colors (black, silver), while the 6D Mark II is only available in black.

If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Pentax K-3 III is notably smaller (12 percent) than the Canon 6D Mark II. However, the K-3 III is markedly heavier (7 percent) than the 6D Mark II. In this context, it is worth noting that both cameras are splash and dust-proof and can, hence, be used in inclement weather conditions or harsh environments.

The above size and weight comparisons are to some extent incomplete since they do not consider the interchangeable lenses that both of these cameras require. Hence, you might want to study and compare the specifications of available lenses in order to get the full picture of the size and weight of the two camera systems.

Concerning battery life, the 6D Mark II gets 1200 shots out of its Canon LP-E6N battery, while the K-3 III can take 800 images on a single charge of its Pentax D-LI90 power pack.

The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you want to switch the focus of the display and review another camera pair, you can move across to the CAM-parator tool and choose from the broad selection of possible camera comparisons there.

Body Specifications

#		Camera Model	Camera Width	Camera Height	Camera Depth	Camera Weight	Battery Life	Weather Sealing	Camera Launch	Launch Price (USD)	Street Price
1.		Canon 6D Mark II	144 mm	111 mm	75 mm	765 g	1200	Y	Jun 2017	1,999	amazon.com
2.		Pentax K-3 III	135 mm	104 mm	74 mm	820 g	800	Y	Mar 2021	1,999	amazon.com
3.		Canon R	139 mm	98 mm	84 mm	660 g	370	Y	Sep 2018	2,299	ebay.com
4.		Canon 5D Mark IV	151 mm	116 mm	76 mm	890 g	900	Y	Aug 2016	3,499	amazon.com
5.		Canon 80D	139 mm	105 mm	79 mm	730 g	960	Y	Feb 2016	1,199	ebay.com
6.		Canon 5D Mark III	152 mm	116 mm	76 mm	950 g	950	Y	Mar 2012	3,499	ebay.com
7.		Canon 6D	145 mm	111 mm	71 mm	770 g	1090	Y	Sep 2012	2,099	ebay.com
8.		Canon 5D Mark II	152 mm	114 mm	75 mm	850 g	850	Y	Sep 2008	3,499	ebay.com
9.		Fujifilm X-H1	140 mm	97 mm	86 mm	673 g	310	Y	Feb 2018	1,899	ebay.com
10.		Nikon D750	141 mm	113 mm	78 mm	750 g	1230	Y	Sep 2014	2,299	ebay.com
11.		Nikon D610	141 mm	113 mm	82 mm	850 g	900	Y	Oct 2013	1,999	ebay.com
12.		Nikon D600	141 mm	113 mm	82 mm	850 g	900	Y	Sep 2012	2,099	ebay.com
13.		Pentax KP	132 mm	101 mm	76 mm	703 g	390	Y	Jan 2017	1,099	ebay.com
14.		Pentax K-70	126 mm	93 mm	74 mm	688 g	410	Y	Jun 2016	649	ebay.com
15.		Pentax K-3 II	131 mm	100 mm	77 mm	800 g	720	Y	Apr 2015	1,099	ebay.com
16.		Pentax K-3	131 mm	100 mm	77 mm	800 g	560	Y	Oct 2013	1,299	ebay.com
17.		Sony A7 III	127 mm	96 mm	74 mm	650 g	610	Y	Feb 2018	1,999	amazon.com
Note: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.
Convert to Imperial

Any camera decision will naturally be influenced heavily by the price. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The two cameras under review were launched at the same price and fall into the same market segment. Normally, street prices remain initially close to the MSRP, but after a couple of months, the first discounts appear. Later in the product cycle and, in particular, when the replacement model is about to appear, further discounting and stock clearance sales often push the camera price considerably down. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.

Sensor comparison

The size of the imaging sensor is a crucial determinant of image quality. A large sensor will tend to have larger individual pixels that provide better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixel-units in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors are more costly to manufacture and tend to lead to bigger and heavier cameras and lenses.

Of the two cameras under consideration, the Canon 6D Mark II features a full frame sensor and the Pentax K-3 III an APS-C sensor. The sensor area in the K-3 III is 58 percent smaller. As a result of these sensor size differences, the cameras have a format factor of, respectively, 1.0 and 1.5. Both cameras have a native aspect ratio (sensor width to sensor height) of 3:2.

With 26MP, the 6D Mark II offers a slightly higher resolution than the K-3 III (25.6MP), but the 6D Mark II nevertheless has larger individual pixels (pixel pitch of 5.76μm versus 3.76μm for the K-3 III) due to its larger sensor. However, the K-3 III is a much more recent model (by 3 years and 9 months) than the 6D Mark II, and its sensor will have benefitted from technological advances during this time that further enhance the light gathering capacity of its pixels. Coming back to sensor resolution, it should be mentioned that the K-3 III has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.

The 6D Mark II has on-sensor phase detect pixels, which results in fast and reliable autofocus acquisition even during live view operation.

Unlike the 6D Mark II, the K-3 III has the capacity to capture high quality composite images (YESMP) by combining multiple shots after shifting its sensor by miniscule distances. This multi-shot, pixel-shift mode is most suitable for photography of stationary objects (landscapes, studio scenes).

The Canon EOS 6D Mark II has a native sensitivity range from ISO 100 to ISO 40000, which can be extended to ISO 50-102400. The corresponding ISO settings for the Pentax K-3 III are ISO 100 to ISO 160000 (no boost).

Technology-wise, both cameras are equipped with CMOS (Complementary Metal–Oxide–Semiconductor) sensors. Both cameras use a Bayer filter for capturing RGB colors on a square grid of photosensors. This arrangement is found in most digital cameras.

Consistent information on actual sensor performance is available from DXO Mark for many cameras. This service is based on lab testing and assigns an overall score to each camera sensor, as well as ratings for dynamic range ("DXO Landscape"), color depth ("DXO Portrait"), and low-light sensitivity ("DXO Sports"). The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.

Sensor Characteristics

#		Camera Model	Sensor Class	Resolution (MP)	Horiz. Pixels	Vert. Pixels	Video Format	DXO Portrait	DXO Landscape	DXO Sports	DXO Overall
1.		Canon 6D Mark II	Full Frame	26.0	6240	4160	1080/60p	24.4	11.9	2862	85
2.		Pentax K-3 III	APS-C	25.6	6192	4128	4K/30p	24.2	13.7	2083	85
3.		Canon R	Full Frame	30.1	6720	4480	4K/30p	24.5	13.5	2742	89
4.		Canon 5D Mark IV	Full Frame	30.1	6720	4480	4K/30p	24.8	13.6	2995	91
5.		Canon 80D	APS-C	24.0	6000	4000	1080/60p	23.6	13.2	1135	79
6.		Canon 5D Mark III	Full Frame	22.1	5760	3840	1080/30p	24.0	11.7	2293	81
7.		Canon 6D	Full Frame	20.0	5472	3648	1080/30p	23.8	12.1	2340	82
8.		Canon 5D Mark II	Full Frame	21.0	5616	3744	1080/30p	23.7	11.9	1815	79
9.		Fujifilm X-H1	APS-C	24.0	6000	4000	4K/30p	24.0	13.3	1806	82
10.		Nikon D750	Full Frame	24.2	6016	4016	1080/60p	24.8	14.5	2956	93
11.		Nikon D610	Full Frame	24.2	6016	4016	1080/30p	25.1	14.4	2925	94
12.		Nikon D600	Full Frame	24.2	6016	4016	1080/30p	25.1	14.2	2980	94
13.		Pentax KP	APS-C	24.1	6016	4000	1080/60i	23.9	13.2	1699	81
14.		Pentax K-70	APS-C	24.0	6000	4000	1080/60i	23.8	13.1	1639	80
15.		Pentax K-3 II	APS-C	24.1	6016	4000	1080/60i	23.6	13.6	1106	80
16.		Pentax K-3	APS-C	24.1	6016	4000	1080/60i	23.7	13.4	1216	80
17.		Sony A7 III	Full Frame	24.0	6000	4000	4K/30p	25.0	14.7	3730	96
Note: DXO values in italics represent estimates based on sensor size and age.

Many modern cameras are not only capable of taking still images, but also of capturing video footage. The two cameras under consideration both have sensors whose read-out speed is fast enough to capture moving pictures, but the K-3 III provides a better video resolution than the 6D Mark II. It can shoot movie footage at 4K/30p, while the Canon is limited to 1080/60p.

Feature comparison

Apart from body and sensor, cameras can and do differ across a range of features. The 6D Mark II and the K-3 III are similar in the sense that both have an optical viewfinder. The latter is useful for getting a clear image for framing even in brightly lit environments. The viewfinder in the K-3 III offers a wider field of view (100%) than the one in the 6D Mark II (98%), so that a larger proportion of the captured image is visible in the finder. On the other hand, the viewfinder of the 6D Mark II has a higher magnification (0.72x vs 0.70x), so that the size of the image transmitted appears closer to the size seen with the naked human eye. The adjacent table lists some of the other core features of the Canon 6D Mark II and Pentax K-3 III along with similar information for a selection of comparators.

Core Features

#		Camera Model	Viewfinder (Type or 000 dots)	Control Panel (yes/no)	LCD Specifications (inch/000 dots)	LCD Attach- ment	Touch Screen (yes/no)	Max Shutter Speed *	Max Shutter Flaps *	Built-in Flash (yes/no)	Built-in Image Stab
1.		Canon 6D Mark II	optical	Y	3.0 / 1040	swivel	Y	1/4000s	6.5/s	n	n
2.		Pentax K-3 III	optical	Y	3.2 / 1620	fixed	Y	1/8000s	12.0/s	n	Y
3.		Canon R	3690	Y	3.2 / 2100	swivel	Y	1/8000s	8.0/s	n	n
4.		Canon 5D Mark IV	optical	Y	3.2 / 1620	fixed	Y	1/8000s	7.0/s	n	n
5.		Canon 80D	optical	Y	3.0 / 1040	swivel	Y	1/8000s	7.0/s	Y	n
6.		Canon 5D Mark III	optical	Y	3.2 / 1040	fixed	n	1/8000s	6.0/s	n	n
7.		Canon 6D	optical	Y	3.0 / 1040	fixed	n	1/4000s	4.5/s	n	n
8.		Canon 5D Mark II	optical	Y	3.0 / 920	fixed	n	1/8000s	3.9/s	n	n
9.		Fujifilm X-H1	3690	Y	3.0 / 1040	full-flex	Y	1/8000s	14.0/s	n	Y
10.		Nikon D750	optical	Y	3.2 / 1229	tilting	n	1/4000s	6.0/s	Y	n
11.		Nikon D610	optical	Y	3.2 / 921	fixed	n	1/4000s	6.0/s	Y	n
12.		Nikon D600	optical	Y	3.0 / 921	fixed	n	1/4000s	5.5/s	Y	n
13.		Pentax KP	optical	n	3.0 / 921	tilting	n	1/6000s	7.0/s	Y	Y
14.		Pentax K-70	optical	n	3.0 / 921	swivel	n	1/6000s	6.0/s	Y	Y
15.		Pentax K-3 II	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	n	Y
16.		Pentax K-3	optical	Y	3.2 / 1037	fixed	n	1/8000s	8.3/s	Y	Y
17.		Sony A7 III	2359	n	3.0 / 922	tilting	Y	1/8000s	10.0/s	n	Y
Note: *) Information refers to the mechanical shutter, unless the camera only has an electronic one.

One feature that differentiates the K-3 III and the 6D Mark II is in-body image stabilization (IBIS). The K-3 III reduces the risk of handshake-induced blur with all attached lenses, while the 6D Mark II offers no blur reduction with lenses that themselves do not provide optical image stabilization.

The Canon 6D Mark II and the Pentax K-3 III both have an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.

Concerning the storage of imaging data, both the 6D Mark II and the K-3 III write their files to SDXC cards. The K-3 III features dual card slots, which can be very useful in case a memory card fails. In contrast, the 6D Mark II only has one slot. The K-3 III supports UHS-II cards (on its first slot), while the 6D Mark II can use UHS-I cards.

Connectivity comparison

For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Canon EOS 6D Mark II and Pentax K-3 III and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.

Input-Output Connections

#		Camera Model	Hotshoe Port	Internal Mic / Speaker	Microphone Port	Headphone Port	HDMI Port	USB Port	WiFi Support	NFC Support	Bluetooth Support
1.		Canon 6D Mark II	Y	stereo / mono	Y	-	mini	2.0	Y	Y	Y
2.		Pentax K-3 III	Y	stereo / mono	Y	Y	micro	3.2	Y	-	Y
3.		Canon R	Y	stereo / mono	Y	Y	mini	3.1	Y	-	Y
4.		Canon 5D Mark IV	Y	mono / mono	Y	Y	mini	3.0	Y	Y	-
5.		Canon 80D	Y	stereo / mono	Y	Y	mini	2.0	Y	Y	-
6.		Canon 5D Mark III	Y	mono / mono	Y	Y	mini	2.0	-	-	-
7.		Canon 6D	Y	mono / mono	Y	-	mini	2.0	Y	-	-
8.		Canon 5D Mark II	Y	mono / mono	Y	-	mini	2.0	-	-	-
9.		Fujifilm X-H1	Y	stereo / mono	Y	-	micro	3.0	Y	-	-
10.		Nikon D750	Y	stereo / mono	Y	Y	mini	2.0	Y	-	-
11.		Nikon D610	Y	mono / mono	Y	Y	mini	2.0	-	-	-
12.		Nikon D600	Y	mono / mono	Y	Y	mini	2.0	-	-	-
13.		Pentax KP	Y	stereo / mono	Y	-	-	2.0	Y	-	-
14.		Pentax K-70	Y	stereo / mono	Y	-	mini	2.0	Y	-	-
15.		Pentax K-3 II	Y	mono / mono	Y	Y	mini	3.0	-	-	-
16.		Pentax K-3	Y	mono / mono	Y	Y	mini	3.0	-	-	-
17.		Sony A7 III	Y	stereo / mono	Y	Y	micro	3.1	Y	Y	Y

It is notable that the K-3 III has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The 6D Mark II lacks such a headphone port.

Studio photographers will appreciate that the Pentax K-3 III (unlike the 6D Mark II) features a PC Sync socket, so that professional strobe lights can be controlled by the camera.

Travel and landscape photographers will find it useful that both cameras feature internal geolocalization sensors and can record GPS coordinates in their EXIF data.

Both the 6D Mark II and the K-3 III are recent models that are part of the current product line-up. The 6D Mark II replaced the earlier Canon 6D, while the K-3 III followed on from the Pentax K-3 II. Further information on the features and operation of the 6D Mark II and K-3 III can be found, respectively, in the Canon 6D Mark II Manual (free pdf) or the online Pentax K-3 III Manual.

Review summary

So what conclusions can be drawn? Is the Canon 6D Mark II better than the Pentax K-3 III or vice versa? A synthesis of the relative strong points of each of the models is listed below.

Advantages of the Canon EOS 6D Mark II:

• Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
• Better live-view autofocus: Features on-sensor phase-detection for more confident autofocus.
• Larger viewfinder image: Features a viewfinder with a higher magnification (0.72x vs 0.70x).
• More flexible LCD: Has a swivel screen for odd-angle shots in portrait or landscape orientation.
• More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
• Longer lasting: Can take more shots (1200 versus 800) on a single battery charge.
• Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
• More heavily discounted: Has been available for much longer (launched in June 2017).

Arguments in favor of the Pentax K-3 III:

• Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
• High quality composites: Can combine several shots after pixel-shifting its sensor.
• Better video: Provides higher definition movie capture (4K/30p vs 1080/60p).
• Better sound control: Has a headphone port that enables audio monitoring while recording.
• More complete view: Has a viewfinder with a larger field of view (100% vs 98%).
• Larger screen: Has a bigger rear LCD (3.2" vs 3.0") for image review and settings control.
• More detailed LCD: Has a higher resolution rear screen (1620k vs 1040k dots).
• Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
• Faster burst: Shoots at higher frequency (12 vs 6.5 flaps/sec) to capture the decisive moment.
• More compact: Is smaller (135x104mm vs 144x111mm) and will fit more readily into a bag.
• Sharper images: Has stabilization technology built-in to reduce the impact of hand-shake.
• Faster data transfer: Supports a more advanced USB protocol (3.2 vs 2.0).
• Better studio light control: Has a PC Sync socket to connect to professional strobe lights.
• Greater peace of mind: Features a second card slot as a backup in case of memory card failure.
• Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
• More modern: Reflects 3 years and 9 months of technical progress since the 6D Mark II launch.

If the count of individual advantages (bullet points above) is taken as a guide, the K-3 III is the clear winner of the contest (16 : 8 points). However, the pertinence of the various camera strengths will differ across photographers, so that you might want to weigh individual camera traits according to their importance for your own imaging needs before making a camera decision. A professional wedding photographer will view the differences between cameras in a way that diverges from the perspective of a travel photog, and a person interested in cityscapes has distinct needs from a macro shooter. Hence, the decision which camera is best and worth buying is often a very personal one.

How about other alternatives? Do the specifications of the Canon 6D Mark II and the Pentax K-3 III place the cameras among the top in their class? Find out in the latest Best DSLR Camera listing whether the two cameras rank among the cream of the crop.

In any case, while the specs-based evaluation of cameras can be instructive in revealing their potential as photographic tools, it remains incomplete and does no justice, for example, to the way the 6D Mark II or the K-3 III perform in practice. User reviews, such as those found at amazon, can sometimes inform about these issues, but such feedback is often incomplete, inconsistent, and biased.

Expert reviews

This is why expert reviews are important. The following table reports the overall ratings of the cameras as published by some of the major camera review sites (amateurphotographer [AP], cameralabs [CL], digitalcameraworld [DCW], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.

Expert Camera Reviews

#		Camera   Model	AP   score	CL   score	DCW   score	DPR   score	EPZ   score	PB   score	Camera Launch	Launch Price (USD)	Street Price
1.		Canon 6D Mark II	4/5	+	4/5	80/100	4.5/5	4/5	Jun 2017	1,999	amazon.com
2.		Pentax K-3 III	4/5	..	3/5	..	4.5/5	..	Mar 2021	1,999	amazon.com
3.		Canon R	4/5	o	4/5	79/100	4.5/5	4/5	Sep 2018	2,299	ebay.com
4.		Canon 5D Mark IV	4.5/5	+ +	4/5	87/100	4.5/5	4.5/5	Aug 2016	3,499	amazon.com
5.		Canon 80D	4/5	+ +	4.5/5	84/100	4.5/5	4.5/5	Feb 2016	1,199	ebay.com
6.		Canon 5D Mark III	..	+ +	..	82/100	4.5/5	4.5/5	Mar 2012	3,499	ebay.com
7.		Canon 6D	5/5	+ +	..	83/100	4.5/5	4.5/5	Sep 2012	2,099	ebay.com
8.		Canon 5D Mark II	4/5	91/100	..	79/100	4/5	..	Sep 2008	3,499	ebay.com
9.		Fujifilm X-H1	..	+	5/5	86/100	4.5/5	4.5/5	Feb 2018	1,899	ebay.com
10.		Nikon D750	5/5	+ +	4/5	90/100	4.5/5	4.5/5	Sep 2014	2,299	ebay.com
11.		Nikon D610	4/5	+ +	..	87/100	4.5/5	4.5/5	Oct 2013	1,999	ebay.com
12.		Nikon D600	4/5	+ +	..	87/100	5/5	4.5/5	Sep 2012	2,099	ebay.com
13.		Pentax KP	4/5	..	3/5	82/100	5/5	4.5/5	Jan 2017	1,099	ebay.com
14.		Pentax K-70	4.5/5	..	4/5	79/100	4.5/5	4.5/5	Jun 2016	649	ebay.com
15.		Pentax K-3 II	4.5/5	..	..	..	5/5	5/5	Apr 2015	1,099	ebay.com
16.		Pentax K-3	4/5	..	..	83/100	5/5	5/5	Oct 2013	1,299	ebay.com
17.		Sony A7 III	..	+ +	4.5/5	89/100	5/5	5/5	Feb 2018	1,999	amazon.com
Note: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.

The review scores listed above should be treated with care, though. The ratings were established in reference to similarly priced cameras that were available in the market at the time of the review. Hence, a score should always be seen in the context of the camera's market launch date and its price, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. It should also be noted that some of the review sites have over time altered the way they render their verdicts.

Check 6D Mark II price at
amazon.com
Check K-3 III price at
amazon.com

Other camera comparisons

Did this review help to inform your camera decision process? In case you would like to check on the differences and similarities of other camera models, just make your choice using the following search menu. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.

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Check 6D Mark II price at
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